. A student obtained a sharp image of a candle flame placed at the distant

end of the laboratory table on a screen using a concave mirror to determine its focal length. The teacher suggested him to focus a distant building about 1km far from the laboratory, for getting more correct value of the focal length. In order to focus the distant building on the same screen the student should slightly move the

(a) mirror away  from  the screen

(b) screen away  from  the mirror

(c) screen towards the mirror    

(d) screen towards the building                             


Best Answer

Ans. (c) screen towards the mirror   

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